Spring data - If primary datasource fails the second does not come up - spring

Question

I am using Spring boot and Spring data and I want to use primarily a MySQL datasource but if fails to connect go to a H2 datasource.
So far, I do the change just moving the #Primary in the configurations, but if I put the #Primary in the MySQL (main data source) and stop the MySQL server in my pc, the other bean does not come up... What do I need?
application.yml:
# Main properties
spring:
application:
name: app
jpa:
database: default
show-sql: false
hibernate:
ddl-auto: update
properties:
hibernate:
format_sql: false
current_session_context_class: org.springframework.orm.hibernate5.SpringSessionContext
# Main database: MySQL
main.datasource:
url: jdbc:mysql://localhost:3306/app?useSSL=false
driver-class-name: com.mysql.jdbc.Driver
username: sa
password: sa
# Backup database: H2
backup.datasource:
url: jdbc:h2:${project.directory}/app;DB_CLOSE_ON_EXIT=FALSE
driver-class-name: org.h2.Driver
username: sa
password: sa
Main data source
#Configuration
#EnableTransactionManagement
#EnableJpaRepositories("org.app")
#EntityScan("org.app")
public class MainDataSourceConfig {
#Primary
#Bean(name = "mainDataSource")
#ConfigurationProperties(prefix = "main.datasource")
public DataSource mainDataSource() {
return DataSourceBuilder.create().build();
}
}
Backup data source:
#Configuration
#EnableTransactionManagement
#EnableJpaRepositories("org.app")
#EntityScan("org.app")
public class BackupDataSourceConfig {
#Bean(name = "backupDataSource")
#ConfigurationProperties(prefix = "backup.datasource")
public DataSource backupDataSource() {
return DataSourceBuilder.create().build();
}
}
Thanks!

Answer 1

I figure out how to do it. Hope this can help anyone:
#Configuration
#EnableTransactionManagement
#EnableJpaRepositories("org.app")
#EntityScan("org.app")
public class DataSourceConfig {
private static final String USERNAME = "sa";
private static final String PASSWORD = "sa";
#Bean
#Primary
public DataSource dataSource() {
DataSource dataSource;
try {
dataSource = getMainDataSource();
dataSource.getConnection().isValid(500);
} catch (Exception e) {
log.error("Main database not valid.", e);
dataSource =getBackupDataSource();
}
return dataSource;
}
private DataSource getMainDataSource() {
return DataSourceBuilder.create()
.driverClassName("com.mysql.jdbc.Driver")
.username(USERNAME)
.password(PASSWORD)
.url("jdbc:mysql://localhost:3306/app?useSSL=false")
.build();
}
private DataSource getBackupDataSource() {
return DataSourceBuilder.create()
.driverClassName("org.h2.Driver")
.username(USERNAME)
.password(PASSWORD)
.url("jdbc:h2:/app;DB_CLOSE_ON_EXIT=FALSE")
.build();
}
}
Just on bean.